Well I don't paint them all at once, just some in little spurts, and they're meant to be $5 paintings so I try not to spend eons on them and mostly use them for experimenting with color and ideas so it helps me out on larger things as well. As for picking and mixing colors, I think at this point it's often just "winging it" but that's from years of messing around with colors - I also try to do color-checking when I paint something that's supposed to be more realistic or based on something that I want a very specific color. I do like painting relatively monochromatic paintings (I'd say 1-3 colors) because I don't have to worry about 'choosing the right color' and I can focus on values, but because of that I think I've learned a bit about color and brands - which ones I like, which ones mix well, etc. Hm... maybe a better example is: I know that a lot of people like to paint out color wheels or color tables that show how various colors look and mix, but since I have tiny paintings I can work on, I can do something similar without being "boring" and I can see what it can actually produce. It's not great as a "reference" since I can't exactly look back on old ones, haha, but I think I learn better by doing, so I remember how I like mixing various things by trying them out. Reds in particular drove me crazy for a long time because I liked starting from transparent colors on dark canvases and then 'bringing up' light with white... that doesn't work out so well with reds unless you want pink
So your question actually ties in to the little paintings - I often 'practice with color' on them
Oh, as for naming colors, though... I'm not sure I'm so great at that either, but I've always been bad at remembering names/titles/places/etc. If I've used a color a lot or got a new one that I really like, sure I might remember it better, but I also have tiny "oil paint sets" that I don't even pay attention to the name so much as the general color on the bottle (which is sometimes misleading, I'll admit, so moreso the color that comes out of the bottle, haha) and just have a general "feel" for. I do know a bit about color theory from books as well, but I have a better feel for it from practice.